'use strict';

function get_letter_interval(number_a, number_b) {
  //在这里写入代码
  var result = [];
  var s = [];
  for (let i = 0; i < 26; i++) {
    s.push(String.fromCharCode(97 + i));
  }
  if (number_a < number_b) {
    for (let i = number_a; i <=number_b; i++) {
      result.push(s[i-1]);
    }
  } else if (number_a >number_b) {
    for (let i = number_a; i >=number_b; i--) {
      result.push(s[i-1]);
    }
  } else {
    result.push(s[number_a-1]);
    return result;
  }
  return result;
}

module.exports = get_letter_interval;
